Short-circuiting device



Sept. 18, 1928. 1,684,941'

K F. J. BuLLlvANr SHORT CIRCUITING DEVICE Filed NOV. 5. 1925 n f be positive in p larged showing lilavtented Sept.y i718, 1*"928.y n

- EE'NCIS TES? rATeNT OFFICE.

J. BULLIVENLOES'I. LOUIS, MISSOURI, `ASSIGNOR To VALLEY ELECTRIC COMPANY,"OE ST. LOUIS, MISSOURLA CORPORATION OE MISSOURI.

- LSHORT-CIRCUITIIIG- DEVICE.

x Application iledlNovember 5, 1925'.l Serial No. 67,111.

yThis invention pertains to a commutator `short-circhiting devicessuchasare used on` alternating current vcommutator motors i One ofthe `objects 'of kthis invention is to 'providea short,circuitingl device which will its Operation and accurate in its setting. l f v Another object of this invention is to provide such a device in which the centrifugal force of the contactors is effective inv operating the device and in which a4 positive and .sudden action-ot the Contactors is insured.

Another yobject is to provide Isuch a vdevice which shall be cheap to manu ple to assemble.v e v c v Further objects will appear from the following/description taken in connectionavith the accompanyingdrawing inwliich y' Y Figure 1 is a fragmentary sectional view of an armature kWith a short circuitingk devic embodying this invention: Y n V Figure` 2 is. a similar view somewhat enthe oontactors lin operative position. y y

r-Referringnovv tothe accompanying drawing 1 designates .the armature shaft `upon which may be mountedl one or more flanges 2 tofsupport the laminae'r. 4A commutator hub 4 mounted' on the iange 2-supports the com-y lmutator segments 5 in y any usual and approved manner. All of this construction may be of anysuitable type'vvell known in the art.

Mountedon theshaft-l and Within` the conr mutator hubll is a metal cup-'6 .formed ot sheet metal and provided with central cylindrical neck radapted to itthe shaft 1 and an outer flange 7 yproviding between it and the i central neck an annular recess vadapted r,to re* ceive the contactorsas will presently be described.v A series of contactors 8,Which may be formed by punching out Of copper or other l suitable material, is provided for short cir is also'p'rovided with a contacting lug 11.

cuitingthe commutator. Each cont-actor is *formedvvith va hooked shaped rear end `9 and a Weightedfront end 10. The Weighted end on its outer edge. 'The hooked ends ot the conta'ctors 'are adapted to seat in the annular recess formed in the cup Ojwhich 1 thus provides a rsupport kfor `the ent-ire series of con` tactors. At'spaced points in the bottom `of 'the cup 6, spacers 12V arer formed by punching the same from the bottom cup and bending 1n-Y j-Wardly as shown in Flgure 2.- These spacers facture andsim- K extend` between thecontactors 10 at certain points andserve to maintain saidcontactors in proper spaced relation and to drive Athe 'same when the armature rotates, and preventf sidewise tipping ot the contactors so as to prevent their disengagement. `These spacers are f slotted to receive the rim lahereinafter deV scribed.' Y Mounted on the supporting cup 6 is a retainer 13 having Va reduced cylindrical portion 14 adapted to lit over the central neck oit the support G, so as to be slidable thereonand y having an outwardly flared rim 15 at thel rear end thereof'.` VThe flared -rini 15'is adaptedto vfit intofthe hooked ends 9 ot'V the assembled seriesot contactors as illustratedy in Figure2.

The retainer 13 is also provided just inside of l by the co-operation of the cup and lthe retainer 13. After assembly the retainer is se@A cured to the support by bending outwardly fromv the support lugs 17 toextend into Openings 1811i the retainer so as to lock theseijiarts together, but at the same time permit a. lim- The assen'ibled device may then be slipped on the shaft after which a Washer 19 ot fibre or Vhen a complete set ot contactors` ited n'iovement of the retainer on the support. i

any` suitable insulating nuiterial nis placed over thel end oft-he retainer 13 and so ast-o close the opening in the.commutator 5, A

governor spring V20 is then .slipped over the shaft and against .the Washer 19 and compressed. A flanged Washer 212isthen slipped over the shait and against the spring. vA

groove 23 in the shaft, after which the washer 21 may be released so as tocover `and retain the' collar 22. This serves to lock the entire =device in place'on the shaft.v

n In the operation of this device, the spring .20 presses rearwardlyupon the retainer 13 which engages the hooked ends 9`o1the contactors atitscam portion 16. The contactors in turn engagethe curved rim 24 of the ,flange v 7 at ai'cam portion 25 on eachcontactor. The` split collar 22 is now Ainserted in an annular Cil pressure of the retainer on the ends of the contactors causes the contactors to pivot at 25 so as to retract said contactors radially inwardly and prevent the same from contactingwith the segments 5, Thisis the position of the device when the armature is at a standstill. As the motor starts the centrifugal force of the weighted ends l0 oft-hecont'actorsf causes the same to tend to move outwardly against the tension of the spring 20. This tendency increases as the speed increases. At a certain pre-determined speed the centrifugal force of the contactors will be sufficient t-o overcome the spring pressure, whereupon the cont actors will move outwardly into Contact with the cominutator segments. During such movementthe contractors pivot at 25 on the support with a sliding movement over the rim Qet. At the same time, the hooked ends 9 move outwardly along the cam portion 1G of the retainer, thereby forcing the retainer to move along the support against the pressure of the spring 20. lt will be noted that on account of the moving pivot at 25,' and also on account of the cam action at 1G, the radial movementof the outer end l0 of the vcontacter is quite large as compared with the movement of the retainer while conipressing the spring. Accordingly, since the spring compression is slight, the difference in spring tension in its outer and inner'positions will be slight. At the Sametime, onaccount of the considerable radial displacement of the weighted end of the contacter, the dierence in its centrifugal force between its inner and the outer positions will be comparatively great. Consequently, the action of the contactors will be 'positive and at the pre-determined speed they will move i outwardly with a sharp snap. This is a very advantageous feature' since it results in a very sudden making or breaking of the contact at the commutator so that comparatively Alittle burning of the contacts can take place. It will be seen, furthermore, that the moving pivot at 25 is of material assistance in bringing about this effect. It will be seen, therefore, that in accordance with this invention a short circuiting device is provided which is posit-ive in its action so that it makes contact vwith a sharp snap. This device furthermore, is very compact and of such simple construction as to be cheaply manufactured and easily and quickly assembled.

It is obvious that various changes may be madein details of construction without departing from the spirit of this invention; it

is, therefore, understood that the inventionl is not to be limited to the specilicdetails shown and described.v

Having thus described the invention, what is claimed is:

l. Arcoininutator short-circuiting device,V

comprising,.a support, a series of vcentrifugalsupport adapted to provide a moving pivot bearing for `said. contactors, a retainer movable on said supportand e'ngagin'g` said contactors to retain the same in inoperative position, means forv tensioning said retainer, and means for interlocking said retainer with said support.

2. A commutator short-circuiting device, comprising, a support, a series of centrifugally operable cont'actors thereon, a part on said support adapted to provide a. moving pivot bearing for said cont-actors, saidsupport hav- -ing an annular recess and said contractors having hooked ends nested in said recess, a retainer movably mounted on said support -and'having a. cam port-ion engaging said hookel ends to retain said contactors ininoperative position, and means for tensioning said retainer.

3. A comn'iutator short-circuiting' device, comprising, a support,a series of centrifugally operable contacto'rs thereon, apart on said support adapted to provide a moving pivot bearing for said contactors, said support having an annular recess and'said contactors having hooked ends nested in said recess, a retainer movably mounted on said support and having a flared rim providing a cam `portion engaging' said hooked" ends jto retain said contactors in inoperative position, and means for tensioning said retainer.

A. commutator yshort-circuiti'ng device, comprising, a support, a series ofcentrifugally operable contact-ors thereon, a-part on said supportadapted to provide a movingpivot bearing for said contactors, said support having an annular recess and saidcon't-actors having hooked ends nested'in said recessfaretainer movably mounted on said support and having a cam surface engaging said hooked ends to retain said contactors in inop'erativ(I position, and means for tensioning fsaid retainer, whereby the centrifugal force of said cont-actors operates through'said cam surface to move said retainer.

5, In an electric motor having a rotor pro-- vided with a comn'iutator, a hollow comm'utator support adapte'd'to support the commutator with the inner faces of itssegments exposed, Ya contacter support. within said commutator `support and having an'an'nular socket the outer edge of which is adapted to provide'a pivot bearing, 'a series of co'ntactors having hooked ends nested in saids'OCket, pivot portions engaging said bearing fand portions adapted to contact with the inner faces of the segments, `and a retainer having a cam' portion yield'ingly engaging said hooked ends to retract said contactorsfrom the commutator.

G. ln an electric motor havinga rotorpro` vided with a commutato'lf, a hollow commutator sulniortadapted to support the commuta- .tor with the inner faces ofjits segmentsexposed, a contacter support within said comniutator support andvhaving an annular socket the outer edge of which is adapted to provide a pivot bearing, a seriesof contac-r torshaving hooked endsnested in said socket, pivot portions engaging said bearing and 'portions adapted to contact with the inner faces of the segments, and aretainer interlocked with saidA contactor support having a cam portion yieldingly engaging'said hooked ends to retract said contactors from vthe cominutator.

7. In an electric niotor having ak commu-y tator, an assembled unit comprising, acontactor support having an annular socket the outer edge oi which 1s adapted to provide a pivot bearing, ak series of contactors having hooked ends nestedin said socket and pivot portions engaging saidjbearing, and a `retainer engaging said hooked ends and interlocked with said support. l

8. In an electric motor having acommutator, an assembled unit comprising, a contactersupport having an annular socket the outer edge of Whichfis adapted to provide a pivot bearing, a seriesof contactors having hooked pivoty portions engaging said bearing andV portions adapted to contact with lthe inner.

faces of the segments, a retainer having a cani portion yieldingly engaging said hooked ends to retract said contactors from the commutator, and a disc closing the bore of the coInmutator and bearing yieldingly against saidy retainer.

In testimony whereof I ailix my signature this 4th day of Sept., 1925.

FRANciS J. BULLIVANT. 

